About the relation of signal - noise

[Tequila]

Dear members of this forum,

I need your help. I have a background line with a relative important noise at 258 nm (the relation of signal - noise) and I think that the problem could be the age of the lamp or any problems in any components of the monochromator.
Thanks in advance for your help,

Diego

[Mark Tracy]

Is this noise random? The most common causes or random noise are
1. Not enough light. Can be caused by contaminated flow cell, high absorbance in the mobile phase, mis-alignment of the flow cell
2. Old lamp
3. Bubbles or particles trapped in the flow cell
4. Incorrect settings for the detector
5. Damaged mirror or grating in the detector optics. This is uncommon.

Is there a pattern in the noise?
1. The pump is not stable; the noise will match the cam cycle of the pump
2. A long-period pattern is usually related to room temperature
3. The heat-exchanger on the flow cell is disconnected

Best of luck